DTEG Updates
ESRA periodically updates the DTEG document. This is typically done at the start of the competition year, but can be updated after that. The document itself takes a while to update, so last year, Jim Jarvis, ESRA Launch Safety Officer, posted a list of the more significant changes as a heads-up to the teams. Jim is doing that again this year, details are as follows.
As you all know, IREC is a Tripoli launch, so the launch must be conducted according to “Tripoli Rules”, including the Tripoli Unified Safety Code (USC). The USC is in the process of being updated by Tripoli, and at a minimum, there will be changes over the coming year to areas such as hybrids/liquids, active controls, and metal in rockets. The updates presented here are based on discussions with Tripoli. Where possible, we have attempted to anticipate the USC changes in the DTEG updates so that the rockets that arrive at the competition will be in compliance with the USC. There are a few topics that are not addressed in the DTEG updates presented here. One area is hybrids and liquids. Liquid rockets will be allowed. Paul Holmes is assisting Tripoli with updates to the USC and will also provide updates to the DTEG. Paul is covering some of this information here on Discord but look for additional information in the coming weeks. Additionally, ESRA is in the process of updating the wiring guidelines. This is long overdue, but ESRA does not have specific changes available at this time.
The list of significant DTEG changes is provided below. As always, there will be many other changes in the document itself, but these are the ones that will most affect your application and planning for the 2027 IREC.
For the competition this year, we want to clarify the roles of Team Mentors versus the Flyer of Record (FoR). One goal is to put more emphasis on the role of Mentor and less emphasis on the role of FoR. In previous years, Teams were required to submit the name of their Flyer of Record (FoR) as part of the application. This year, the FoR will not need to be designated until the first progress report, which is typically in mid-December. FoR’s must be familiar with the project, review the team progress reports to identify any issues of concern, and then attend the competition. The role of the FoR at the competition is unchanged.
However, as part of the application, teams must submit the names of mentors that have agreed to support the team, and then provide a summary of their experience as it pertains to the proposed project. Mentors can provide their experience in many areas; however, ESRA wants teams to do their best to enlist mentors that have high-power rocketry experience (particularly for first-time teams and teams in the more advanced categories) and to seek the guidance of their mentors as early as possible, beginning with the application itself. ESRA's intent is that the role of the mentor for an IREC team be analogous to the role of a TAP for a Level 3 certification project. Mentors are not required to attend the competition although a mentor may also serve as the FoR.We need to limit the number of transmitters. The rules regarding the number of transmitters are as follows:
--- For the purpose of discussing the number of allowable transmitters, the term "congested frequency bands" refers to transmissions in 440 and 900MHz, and 1.2, 2.4 and 5.8GHz. ---Teams are required to have a Primary COTS GPS in each independently-recovered section of the rocket. ESRA will attempt to deconflict these transmitters. --- Teams are permitted one additional congested-band transmitter in each independently recovered section of the rocket. ESRA will attempt to deconflict these transmitters. --- Teams are allowed an additional congested-band SRAD transmitter in an attached or tethered payload as long as the transmitter is associated with the operation of the payload. That is, a team could use this allowance to transmit payload telemetry, but not backup GPS for the rocket. ESRA will attempt to deconflict these transmitters. --- Teams can operate one additional SRAD transmitter in a band outside of the congested bands. ESRA will not attempt to deconflict these transmitters. ---Teams can include an additional transmitter if they are participating in the Live Video Challenge.ESRA plans to again assign transmitter frequencies in the “congested bands”. With the exception of the Primary COTS GPS frequencies in 440MHz, which will again be preassigned in 2027, these assignments will be made at the time of the Final Flight Safety Review. Going forward, teams will need to make frequency adjustments quickly and without the need to remove shear pins or access the interior of the rocket. Teams will either need to make frequency adjustments via the radio itself or through an external connection or access point such as a hatch.
The current DTEG discusses preferences for 900MHz frequency assignments for international teams that are unable to obtain reciprocal HAM licenses (that would allow operation in other bands). This preference will be eliminated in 2027 for several reasons. Many teams moved their transmitter operations to 440MHz. This, combined with certain technical advancements, will relieve much of the congestion in 900MHz. In addition, most international teams have access to reciprocal agreements and can obtain them if they choose to. Finally, rules related to the need for a team member HAM license will be relaxed.
Teams are encouraged to have multiple team members with HAM licenses. However, going forward, teams will be allowed to use the HAM license of their mentor, their FoR, or an ESRA volunteer for any transmission requiring a HAM license. These persons will need to agree to provide this service to the team, the license holder's call sign must be included in the transmission, and the license holder must be present any time that the radio is in operation.
A HAM license is required for any video transmission from the rocket, and the HAM call sign must be displayed on screen.
The DTEG requirements will be clarified so that it is clear that SRAD motor testing, as well as approval of the results by the ESRA safety reviewer, must be completed prior to submitting the Final Technical Report. This deadline typically occurs around May 1.
SRAD motors based on the use of ammonium nitrate are prohibited.
While SRAD altimeters are allowed to perform recovery operations (i.e., fire ejection charges), proof of function is required to allow this. Although flight testing is not specifically required, there must be sufficient testing indicating that the SRAD altimeter is likely to function correctly. Simple verification of the function of a barometric sensor, for example, is not sufficient for proof of function. Going forward, any SRAD altimeter that has not been successfully flight tested must be designed such that it can be easily replaced by a COTS altimeter if required by the ESRA safety reviewer.
Rules associated with active controls will be modified to align them with anticipated changes in the Tripoli USC. Going forward, active controls must fail neutral (an existing DTEG requirement). However, certain other requirements will be eliminated. Specifically, operation of the active controls will be allowed during the motor burn and there will not be a requirement to shut off controls if tilt exceeds 30%. Note that Tripoli anticipates updating the USC in early 2027, and updates to the DTEG may be required.
The DTEG currently requires a calculation showing that the fin flutter velocity exceeds the maximum flight velocity by 50%. This numerical requirement will be eliminated because of the widely varying methods that can be used to calculate the flutter velocity. The requirement for a flutter analysis will be retained, and ESRA safety reviewers can still comment on fin design and/or require changes in fin design or characteristics if they deem this to be necessary.
It is anticipated that Tripoli will revise the USC to clarify the use of metal in rockets. Although it is not clear when this update will occur, it is unlikely that the use of significant quantities of metal, other than aluminum (where necessary), will be allowed. Based on discussions with Tripoli, the following guidelines will be incorporated into the DTEG. Steel, along with other heavy or toxic metals, will not be allowed for airframe structures or for ballast. Steel may be used for components such as recovery system attachment points, minor components in motors, and for sugar motor nozzles as described in the USC. Titanium is not allowed for fins, nose cone tips or other such uses. Note that the use of steel cubesat frames is specifically prohibited.
The airframe structure rules will be modified to allow the use of head-end deployment for COTS nosecones that are provided by the manufacturer with a sliding coupler joint that is less than 1 caliber. This was allowed in 2026.
Teams must design their rockets so that hand-operated switches can be safely operated using either ESRA or team-provided infrastructure. In the specific case of two-stage rockets using the ESRA pads, hand-operated switches cannot be located at a point greater than 15 feet above the aft end of the rocket.
Teams are allowed to bring their own pads to IREC. However, a justification is required for the use of team-provided pads. That is, there must be an acceptable reason why the team is unable to use the ESRA-provided pads.
No changes are proposed for battery-related rules or stability rules, including the rule that prohibits fin spans of less than 0.8 calibers. "Guided Recovery" for rockets and payloads will continue to be prohibited.
Visit our Official ESRA Discord for additional information or email launchsafety@esrarocket.org.